1. Field of the Invention
The present invention relates to an Internal Control Message Protocol (ICMP) of an Internet Protocol (IP), and more particularly to a method for reporting a transmission state to a destination by the ICMP of the IP and a network system using the same.
2. Description of the Related Art
Generally, since the Internet Protocol (IP) does not support an error reporting function and an error correction function for transmission of requested datagrams, even when the datagrams fail to normally reach a corresponding destination, the source (of the transmission) cannot recognize the failure of the normal transmission of the datagrams.
Accordingly, the conventional IP employs an Internet control message protocol (ICMP) for feeding back information to the source (which initially transmitted datagrams) about the failure of the normal transmission of the datagrams.
In detail, the ICMP reports information about causes of the failure of the normal transmission to the source, through an error reporting message, which prevented transmission of relevant datagrams, ensuring the transmission of requested diagrams.
However, since the ICMP reports to the source and not to the destination, the destination is not informed of the failure of the normal transmission.
In detail, a recent mobile communication network employs an IS-2000 network together with an IS-95 network, and the IS-2000 network and the IS-95 network have queues of different sizes for transmitting/receiving datagrams. In other words, a packet data serving node (PDSN) (a router of the IS-2000 network) has a queue larger than that of an inter working function (IWF) (a router of the IS-95 network).
Thus, when a terminal capable of suitably transmitting/receiving datagrams for the queue size of the PDSN in the IS-2000 network is used in a service area of the IS-95 network, the IWF of the IS-95 network cannot normally process datagrams transmitted by the terminal.
For this reason, the IWF reports a transmission errors of the datagrams to the terminal of the source based on the ICMP when the IWF cannot normally process the datagrams.
However, it is difficult for a destination terminal to understand the reason of the transmission error without damage of radio data or point-to-point protocol packets, and may degrade a mobile communication network's reliability.
In this case, it is necessary for the manager of the mobile communication network to analyze the entire network in order to determine the cause of the above-described transmission failure problem. However, since the conventional ICMP reports a transmission problem occurring situation to only the source terminal, the destination terminal cannot easily detect transmission states of datagrams.
Accordingly, the destination terminal strongly requires a technique of reporting transmission states of datagrams thereto through the conventional ICMP of the IP in order to enhance the network efficiency and to improve current analysis methods used to analyze the mobile communication network.